Act 6 of Homestuck is divided into sub-acts and is the longest act so far. The sub-acts focus on the new instances of the kids in the new version of the universe after the Scratch: Jane Crocker, Jake English, Roxy Lalonde, and Dirk Strider, as well as the mysterious cherub characters Calliope and Caliborn. The intermissions follow the old kids and trolls meeting and traveling to the Scratched session, as well as introducing the pre-Scratch trolls, and showing Caliborn exploring his planet.
According to this page, the number of green curtains in Seer: Descend, and the number of remaining unopened green curtains in Caliborn: Enter., there was presumed to be a total of six sub-acts. This was later confirmed when Disc 2 ended.